"The Sanskrit word 'yantra' derives
from the root 'yam' meaning to sustain, hold or support the energy inherent
in a particular element, object or concept. In its first meaning, 'yantra' may
refer to any kind of mechanical contrivance which is harnessed to aid an enterprise.
A yantra in this sense, therefore, is any sort of machine or instrument such
as is used in architecture, astronomy, alchemy,
chemistry, warfare or recreation. A Sanskrit
text of the eleventh century AD, Samaranganasutradhara, on the science of architecture,
gives vivid descriptions of the making and operating of such mechanical yantras
as a wooden flying bird, wooden aeroplanes meant to fly
with hot mercury
as fuel, male and female robot figures, etc. The vast observatories built in
Delhi and Jaipur under the patronage of Jai Singh (1686-1734) are called Jantar-Mantar,
as their massive structures are astronomical 'instruments' (yantras) for recording
heavenly phenomena.

The meaning of the term yantra
has been expanded to refer to religious enterprises, and has acquired a
special theological significance. Mystic yantras are aids to and the chief
instruments of meditative discipline. Basically a yantra used in this context
and for this purpose is an abstract geometrical design intended as a 'tool'
for meditation and increased awareness."...

"In our ordinary perceptions
we view space as an amorphous entity which is related to us in units of
measurment. For us space is essentially quantitative; we understand it
in terms of dimension,
volume and distance. For the adept who uses yantras in yogic meditation,
on the other hand, space enclosed within the bounded figure is purely qualitative;
space is absolute void and unity is a 'sacrament' by means of which he
communicates with a force
that stands for life itself.

The yantra is an archetypal
unity, and in the making of every new yantra the archetypal activity and
the divine revelations repeat themselves. Each yantra's consecrated place
acts as a dwelling for the gods, a space where movement from the level
of profane existence to the level of profound realities is made possible.
Symbol and meaning blend so closely that they are one reality,
indistinguishable from one another."...

"Every yantra creates a power-field,
a cosmicized circuit (kshetra) in which the powers of the sacred are invoked.
The lines and planes localized within the yantra, though distinct from
all the spaces that surround its outer circuit, are an expression of a
transcendental reality. Stretching from star to star the ultimate substratum
of all forms is space. Empty space is in itself a primordial substance
and shares in the nature of divinity. Without it, the primordial substance
whose abode is the whole universe would remain without support. Absolute
void is defined by Indian philosophers as alimitless sea of undifferentiated
continuum which is an ever present entity not detachable from the relative,
thus making all division of space illusory. So the spaces within a yantra,
however minute, can be symbolically brought to 'presence' and expressed
as being as immense as the spaces within the solar system. Although in
the abstract this is the immutable principle on which the space concept
of yantras functions, on the level of human experience we are led to locate
the sacred by creating spatial divisions. The act of bounding the figure,
'fencing' its four quarters, defining its spatial orientations, delimiting
the sacred territory of the yantra, is an act of asserting where sacred
space begins to manifest."...

"The Sri Yantra, considered the greatest of all
yantras, displays the splendour of Siva-Sakti in their manifestation in
order to create the root principles of life (tattvas). A graphic synthesis
of the abstruse cosmological and metaphysical
theory of Saiva-Sakta, the Sri Yantra is to be read as a chart of the evolution
of the cosmic scheme, exposing step by step the theory of creation and
its categories. it also demonstrates how the passage from formlessness
to form takes place, as the antagonistic principles of life emanate and
differentiate themselves from the original wholeness of Siva-Sakti.
The Sri Yantra marks each phase of cosmic evolution and articulates every
descending level of the creativeprocess."